New: File Converter

Convert files locally — including Word and Excel.

Images, whole PDFs, Word DOCX, Excel XLSX, text, code, CSV and JSON stay on your device. KitLumo never receives or stores a copy.

PDF · Word · Excel · Images

Free Calculators

Compound Interest

Straightforward tools that work right here on your phone, tablet or computer. No account, no AI, no nonsense.

Your tool data stays on this device. Anything you type, paste, calculate or open in a tool is not sent to us. KitLumo does not receive it or save a copy.
141 free tools Browser-first No account

Free Calculators

How to use the Compound Interest

Project how savings or an investment could grow when interest is added back to the balance over time. Include regular contributions if they apply to your plan.

  1. Enter or choose the information requested by the tool.
  2. Check the result and change an input if you want to compare another scenario.
  3. Copy, download or use the result when it fits your task.

Using the result

This is an illustration, not a promise of returns. Real rates, tax, fees and market changes can alter the outcome.

Your tool entries are handled in your browser and are not sent to or saved by KitLumo.

Browse by category

Practical guides

Understand the result, not just the number.

Short, plain-language guides explain the assumptions, privacy and limits behind the most important KitLumo tools.

View all guides

Explore related calculators

Related Calculators

7 tools

R+
New

Calculators

Compound Interest

Estimate investment growth with recurring contributions.

Open →
⇡
New

Calculators

Retirement Calculator

See how savings and monthly contributions could grow over time.

Open →
◎
New

Calculators

Savings Goal Calculator

Estimate how long it could take to reach a savings target.

Open →
%
New

Calculators

Savings Rate Calculator

Find the percentage of your monthly income you save.

Open →
CAGR
New

Calculators

CAGR Calculator

Calculate the compound annual growth rate of an investment.

Open →
↗
New

Calculators

Inflation Calculator

Estimate future costs and the effect on buying power.

Open →
%
New

Calculators

Simple Interest Calculator

Calculate interest without compounding.

Open →

Tool workspace

Word Counter

Help shape KitLumo

Don’t see what you need?

Tell us the task you are trying to solve. The most-requested tools guide what we build next.

How KitLumo stays free

Supported by ads. Helped by people.

Clearly labelled ads fund the website so everyone can use every tool for free. If KitLumo saves you time, you are also welcome to make an optional donation to help pay for hosting and keep the tools available.

Donating never unlocks extra features. Every tool remains free for everyone.
Donations are not enabled right now.

How it works

Free means free.

KitLumo is built around small, focused utilities. No login walls, no artificial limits and no AI layer where a reliable tool will do.

Every tool currently available works directly on the phone, tablet or computer you are using. Anything you type, paste, calculate or open in a tool is not sent to us, and KitLumo does not save a copy.

Your saved and recently used tool shortcuts are stored only in your browser on this device. When you use “Report a problem” or “Request a free tool,” only that message and any email address you choose to add are sent to KitLumo.

Help shape KitLumo

Request a tool